﻿using System;
using Bing.Datas.Sql.Builders;

// ReSharper disable once CheckNamespace
namespace Bing.Datas.Sql
{
    /// <summary>
    /// From子句扩展
    /// </summary>
    public static partial class Extensions
    {
        /// <summary>
        /// 设置表名
        /// </summary>
        /// <typeparam name="T">源类型</typeparam>
        /// <param name="source">源</param>
        /// <param name="table">表名</param>
        /// <param name="alias">别名</param>
        /// <returns></returns>
        public static T From<T>(this T source, string table, string alias = null) where T : IFrom
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (source is IClauseAccessor accessor)
            {
                accessor.FromClause.From(table, alias);
            }

            return source;
        }

        /// <summary>
        /// 设置子查询表
        /// </summary>
        /// <typeparam name="T">源类型</typeparam>
        /// <param name="source">源</param>
        /// <param name="builder">Sql生成器</param>
        /// <param name="alias">表别名</param>
        /// <returns></returns>
        public static T From<T>(this T source, ISqlBuilder builder, string alias) where T : IFrom
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (source is IClauseAccessor accessor)
            {
                accessor.FromClause.From(builder, alias);
            }

            return source;
        }

        /// <summary>
        /// 设置子查询表
        /// </summary>
        /// <typeparam name="T">源类型</typeparam>
        /// <param name="source">源</param>
        /// <param name="action">子查询操作</param>
        /// <param name="alias">表别名</param>
        /// <returns></returns>
        public static T From<T>(this T source, Action<ISqlBuilder> action, string alias) where T : IFrom
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (source is IClauseAccessor accessor)
            {
                accessor.FromClause.From(action, alias);
            }

            return source;
        }

        /// <summary>
        /// 添加到From子句
        /// </summary>
        /// <typeparam name="T">源类型</typeparam>
        /// <param name="source">源</param>
        /// <param name="sql">Sql语句。说明：将会原样添加到Sql中，不会进行任何处理</param>
        /// <returns></returns>
        public static T AppendFrom<T>(this T source, string sql) where T : IFrom
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (source is IClauseAccessor accessor)
            {
                accessor.FromClause.AppendSql(sql);
            }

            return source;
        }

        /// <summary>
        /// 添加到From子句
        /// </summary>
        /// <typeparam name="T">源类型</typeparam>
        /// <param name="source">源</param>
        /// <param name="sql">Sql语句。说明：将会原样添加到Sql中，不会进行任何处理</param>
        /// <param name="condition">该值为true时添加Sql，否则忽略</param>
        /// <returns></returns>
        public static T AppendFrom<T>(this T source, string sql, bool condition) where T : IFrom
        {
            return condition ? AppendFrom(source, sql) : source;
        }
    }
}
